/*
    Carracci Systems - Carracci Server (openbam project)
    Copyright (C) 2007  Carracci Systems

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package org.openbam.core.expr;

import org.openbam.core.Event;
import org.openbam.core.TickEvent;


/**
 * Execute the expression for the given event.
 * Expressions are guaranteed to receive events in sequence.
 *
 * @author inder
 */
public interface IExpression {

    String getName();

    /**
     * An expression will get a tick event if it is idle.
     * TickEvent sets the current time to now, whereas an expression may be dealing with
     * events on a different timeline - therefore, be careful when dealing with these
     * events.
     * The sole purpose of this event is to give you a chance to do some processing.
     *
     * @param event
     * @return
     */
    Object evaluate(TickEvent event);

    /**
     * Evaluate the event, and return its value after evaluation.
     *
     * @param event
     */
    Object evaluate(Event event);

    /**
     * Get the current evaluated value of this expression.
     *
     * @return
     */
    Object getValue();

    Double getDoubleValue();

    String getStringValue();

    Boolean getBooleanValue();

    IExpression newInstance();
}
